A comparative study of terfenadine at two dose levels in the management of hayfever

One hundred and twenty patients with hayfever were enrolled in a single-centre, double-blind crossover study designed to compare the efficacy and safety of terfenadine at doses of 60 mg bd and 120 mg bd. A two-week placebo run-in period was followed by the two treatment periods, each lasting two weeks. Assessments of hayfever symptoms were made daily by patients and at each clinic visit by the investigator. Adverse events were recorded at the end of each treatment period. At the end of the study both investigator and patient rated the overall efficacy and the patient recorded treatment preference. The data were examined by analysis of variance (ANOVA) for treatment, period and crossover effects. Pollen counts were recorded for the duration of the study. Seventy-four patients completed the study, the majority of withdrawals occurring during the placebo phase. There was no significant difference in symptom relief between the two doses of terfenadine. The number of adverse events, including drowsiness, was similar for the two treatments and for placebo. Mean and peak pollen counts both correlated well with symptom severity. These data show that terfenadine 60 mg bd is an adequate dose for the treatment of hayfever symptoms.